In partitions such as floors, walls and ceilings made of poured concrete it is necessary to have openings for admitting pipes conducting liquids such as water and liquid wastes and the like. In order to prevent fire from spreading from one side of a partition to the other side, such openings must be filled with fire resistant materials in order to meet existing fire protection codes.
In recent years it has become the practice to use pipes made of plastic, such as polyvinyl chloride and the like instead of steel, cast iron and copper as used in earlier times.
Since plastic pipes become soft, melt and burn at elevated temperatures that normally would not affect metal pipes, it has become necessary to introduce a fire barrier that obturates not only the space around the pipes, but also the empty space remaining after a plastic pipe has melted or burned away.
Several inventions have shown devices for solving this problem. U.S. Pat. No. 4,796,401, for example, shows a composite fire stop device including a collar that can slide over a plastic pipe and fill the space between the poured concrete and the pipe. The collar includes an intumescent material packed around the collar, and circular tension springs that constrict the pipe as it becomes soft from the heat of the fire, while the intumescent material expands and obturates the void created by the melting pipe. U.S. Pat. No. 4,538,389 shows a fire-break device which includes a two-part collar of substantially incombustible material mounted around the pipe, and a slidable flange filling a space between the pipe and the collar. U.S. Pat. No. 4,221,092 shows a fire barrier including a packing of intumescent material packed into the space between a pipe and the poured concrete.
The fire barrier devices of the prior art have, however, certain disadvantages in that they do not show a self-contained single assembly that can be readily installed on a construction site, and become an integral part of a pipe system. Applicants ' invention overcomes these problems by providing a self-contained, one-piece assembly that is an integral part of a pipe system for fluid-filled and air-vented PVC pipe systems, which has the further advantages of including a metallic casing that allows the firestop material to be replaced if needed, and has no external parts to activate or control intumescent action. Furthermore, it avoids the need for drilling holes in concrete partitions; is not unnecessarily complex or costly; and avoids unnecessary cutting and splicing of PVC pipe.